Heart assist devices or pumps can be inserted in the circulatory system to pump blood from either ventricle or atrium of a heart to the vasculature. A pump supplementing a ventricle is known as a ventricular assist device, or VAD. A VAD is useful when the ventricle alone is incapable of providing adequate blood flow. A pump can also completely replace the function of a ventricle. It is known to use two blood pumps, one assisting or replacing the right ventricle and one assisting or replacing the left ventricle.